Created attachment 100166[details]
screenshot
I got a feedback from Japanese user. It seems that mercurial support does not handle Japanese on 6.9 but it works on 6.8. It's a regression from 6.8.
I tried the following steps on both NetBeans 6.8 and 6.9.
1. Start NetBeans on Japanese Windows
As you know, Japanese Windows is using windows-31j encoding, not UTF-8.
2. Create a project on NetBeans (I'll attach a zip for the projects later)
Project encoding is UTF-8 by default.
3. Create a Java source file as Japanese name
4. Init repository of mercurial for the project
5. commit
6. Edit some files and commit them
On NetBeans 6.9, japanese characters are garbled on output window and commit window. (See screenshot).
It works on NetBeans 6.8.
The original issue reported from user is:
1. Created a project on 6.8 and made it as mercurial project
2. It contains Japanese filename
There is no project when user commit the sources on NetBeans 6.8. However,
3. Start NetBeans 6.9
4. Open the project and try to commit some files
=> error happens (see screenshot)
So user can not use the old project now.
Is there any quick workaround until it's fixed?

mercurial plugin is unusable on windows with national characters in filenames (not just with japanese but e.g. czech chars too). Should be fixed ASAP and integrated into 6.9.1
caused by the fix for bug #155147

6.9.1 is close to Code Freeze ... so I tried to use it with other languages and haven't encountered any issues - so marked as verified in continuous build from deadlock, to let it be integrated into 6.9.1 on time.
Masaki, it would be still good to see an verification from you, thanks in advance.